Unsure what kind of motor a couch needs

Electric Motors and Controllers
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qaute
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Unsure what kind of motor a couch needs

Post by qaute » Dec 20, 2017 4:57 pm

Go easy on me; first post here.

I'm in this robotics club (UT Austin IEEE RAS), in which we're roboticizing a couch (or, rather, doing it a second time, better). The general idea: motors to wheels on each side of a frame that the couch sits on top of. A previous, mostly broken version is demoed at <https://www.youtube.com/watch?v=kaYiUHjtGvY>. This couch can't handle multiple people, so we're rebuilding it from scratch. To that end, we need better motors.

At the moment, we have a couple CIM motors plus an AndyMark gearbox on each side. Here are our current thoughts: rebuilding, we'll probably end up with a 12 to 48 V DC system (which one depends on the motor), control logic is a breeze for us, and we have very little idea what kind of motor and controller is best. If it exists, a direct drive 24V to 48V DC brushless motor feels right, but we've no idea where to find one. We assume the couch plus people masses up to half a ton.

Do y'all have any suggestions? What should we be looking for?

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amberwolf
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Re: Unsure what kind of motor a couch needs

Post by amberwolf » Dec 21, 2017 2:12 am

Well, you could probably copy what I have on my SB Cruiser trike; somewhere in the last few pages of the thread in my signature is a list of what's on it presently (I think I upgraded the shunt/current on one of the controllers after that post, so you can look thru the subsequent posts for changes made). It'll haul itself plus a trailer plus nearly 600lbs of dog food easily enough, at 20MPH (probably faster, but that's the limit here). I'm sure it can haul more load than that; just haven't tried yet. :)

I don't know how far these two couch projects got, or if what they did is applicable to yours, but:
https://endless-sphere.com/forums/viewt ... ilit=couch
https://endless-sphere.com/forums/viewt ... ilit=couch

and this project
https://endless-sphere.com/forums/viewt ... ilit=couch
moves several people sitting on it's bench (that IIRC surrounds the central core)


You can also go to http://ebikes.ca/simulator and play with it to see what kind of hubmotor system might work best, and what kind of battery needs you might have. I recommend using "custom controller" and "custom battery" so you can set limits where you need them, vs the pre-setup simulated controllers.

FWIW, if you do use hubmotors, and you'll always run at low speeds, geared hubs in very small wheels would be more efficient than DD hubmotors.

Alternately, brushed powerchair motors that include gearboxes (many have axle moutns too) might work, if you used enough of them. Not as efficient as brushless, but cheap and easy to find used. (not cheap new).

Also nt cheap new, nor as easy to find used, are brushless DD powerchair motors, which are meant for low speeds and high loads. And on the chairs I've seen them on, they use 12-14" wheels with solid tires on them. Not a very nice ride at faster speeds but fine at slow ones (walking, maybe jogging speeds).

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